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      1 /*
      2  * Copyright (C) 2010, 2011 Apple Inc. All rights reserved.
      3  *
      4  * Redistribution and use in source and binary forms, with or without
      5  * modification, are permitted provided that the following conditions
      6  * are met:
      7  * 1. Redistributions of source code must retain the above copyright
      8  *    notice, this list of conditions and the following disclaimer.
      9  * 2. Redistributions in binary form must reproduce the above copyright
     10  *    notice, this list of conditions and the following disclaimer in the
     11  *    documentation and/or other materials provided with the distribution.
     12  *
     13  * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
     14  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
     15  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
     16  * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
     17  * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
     18  * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
     19  * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
     20  * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
     21  * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
     22  * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
     23  * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
     24  */
     25 
     26 #ifndef ColumnInfo_h
     27 #define ColumnInfo_h
     28 
     29 #include "platform/LayoutUnit.h"
     30 #include "wtf/Vector.h"
     31 
     32 namespace WebCore {
     33 
     34 class ColumnInfo {
     35     WTF_MAKE_NONCOPYABLE(ColumnInfo); WTF_MAKE_FAST_ALLOCATED;
     36 public:
     37     ColumnInfo()
     38         : m_desiredColumnWidth(0)
     39         , m_desiredColumnCount(1)
     40         , m_progressionAxis(InlineAxis)
     41         , m_columnCount(1)
     42         , m_columnHeight(0)
     43         , m_minimumColumnHeight(0)
     44         , m_forcedBreaks(0)
     45         , m_maximumDistanceBetweenForcedBreaks(0)
     46         , m_forcedBreakOffset(0)
     47     {
     48     }
     49 
     50     LayoutUnit desiredColumnWidth() const { return m_desiredColumnWidth; }
     51     void setDesiredColumnWidth(LayoutUnit width) { m_desiredColumnWidth = width; }
     52 
     53     unsigned desiredColumnCount() const { return m_desiredColumnCount; }
     54     void setDesiredColumnCount(unsigned count) { m_desiredColumnCount = count; }
     55 
     56     enum Axis { InlineAxis, BlockAxis };
     57 
     58     Axis progressionAxis() const { return m_progressionAxis; }
     59     void setProgressionAxis(Axis progressionAxis) { m_progressionAxis = progressionAxis; }
     60 
     61     unsigned columnCount() const { return m_columnCount; }
     62     LayoutUnit columnHeight() const { return m_columnHeight; }
     63 
     64     // Set our count and height.  This is enough info for a RenderBlock to compute page rects
     65     // dynamically.
     66     void setColumnCountAndHeight(int count, LayoutUnit height)
     67     {
     68         m_columnCount = count;
     69         m_columnHeight = height;
     70     }
     71     void setColumnHeight(LayoutUnit height) { m_columnHeight = height; }
     72 
     73     void updateMinimumColumnHeight(LayoutUnit height) { m_minimumColumnHeight = std::max(height, m_minimumColumnHeight); }
     74     LayoutUnit minimumColumnHeight() const { return m_minimumColumnHeight; }
     75 
     76     int forcedBreaks() const { return m_forcedBreaks; }
     77     LayoutUnit forcedBreakOffset() const { return m_forcedBreakOffset; }
     78     LayoutUnit maximumDistanceBetweenForcedBreaks() const { return m_maximumDistanceBetweenForcedBreaks; }
     79     void clearForcedBreaks()
     80     {
     81         m_forcedBreaks = 0;
     82         m_maximumDistanceBetweenForcedBreaks = 0;
     83         m_forcedBreakOffset = 0;
     84     }
     85     void addForcedBreak(LayoutUnit offsetFromFirstPage)
     86     {
     87         ASSERT(!m_columnHeight);
     88         LayoutUnit distanceFromLastBreak = offsetFromFirstPage - m_forcedBreakOffset;
     89         if (!distanceFromLastBreak)
     90             return;
     91         m_forcedBreaks++;
     92         m_maximumDistanceBetweenForcedBreaks = std::max(m_maximumDistanceBetweenForcedBreaks, distanceFromLastBreak);
     93         m_forcedBreakOffset = offsetFromFirstPage;
     94     }
     95 
     96 private:
     97     LayoutUnit m_desiredColumnWidth;
     98     unsigned m_desiredColumnCount;
     99     Axis m_progressionAxis;
    100 
    101     unsigned m_columnCount;
    102     LayoutUnit m_columnHeight;
    103     LayoutUnit m_minimumColumnHeight;
    104     int m_forcedBreaks; // FIXME: We will ultimately need to cache more information to balance around forced breaks properly.
    105     LayoutUnit m_maximumDistanceBetweenForcedBreaks;
    106     LayoutUnit m_forcedBreakOffset;
    107 };
    108 
    109 }
    110 
    111 #endif
    112